Abstract
The purpose of our study was to establish methods of conducting dental health surveys on 1Y6M old children, to find systemic oral diseases and to prevent dental caries. The subjects were children,1Y6M to 3Y6M old at 9 localities in Japan (Iwamizawa, Morioka, Sendai, Tokyo, Yokosuka, Ibaragi, Tokushima, Hiroshima, Fukuoka), and who were examined every 6 months. Also questionnaires given to their mothers were investigated.
In this report, the relationship between the environmental factors of children in the prenatal and postnatal periods (mother's age, order of birth of the children, the course of the pregnancy, trouble at birth, season at birth, the period of pregnancy, body weight at birth and the form of feeding) and the rate of eruption of the de- ciduous cuspids and the 2nd deciduous molars and the types of eruption were examined.
The results were as follows.
1. Mother's age The rate of the eruption of the deciduous teeth of children showed a higher rate the older the mothers were.
2. Order of the birth of the children (1 st born,2 nd born etc. ) The rate of the eruption of the deciduous teeth of children showed a higher rate as the order of birth increased.
3. Course of pregnancy This factor showed no significant relationship to the eruption of the deciduous teeth.
4. Trouble at birth The rate of the eruption of the deciduous teeth of children whose mothers had no trouble at birth showed a somewhat higher rate than of those whose mothers had trouble.
5. Season at birth The rate of the eruption of the deciduous cuspids of children who were born in winter showed a lower rate than of the others at 1Y6M of age, and the rate of the eruption of the 2 nd deciduous molars of children who were born in autumn showed a higher rate than of the others at 2YOM and 2Y6M of age.
6. Period of pregnancy At 1Y6M,2YOM and 2Y6M of age, the rate of the eruption of the deciduous teeth of children showed a higher rate as their mothers had longer periods of pregnancy.
7. Body weight at birth At 1Y6M,2Y0M and 2Y6M of age, the rate of the eruption of the deciduous teeth of children showed a higher rate the heavier they weighed at birth, but the rate of the eruption of the deciduous teeth, except of the upper 2 nd deciduous molars, of children who weighed more than 4501 g at birth showed a lower rate than that of the others.
8. Feeding form The rate of the eruption of the deciduous cuspids of children who were breastfed showed a somewhat lower rate than that of the others at 1Y6M of age, and the rate of the eruption of 2 nd deciduous molar of children who were bottlefed showed a higher rate than that of the others at 2YOM and 2Y6M of age.
